To produce its first atomic bomb from 20 percent enriched uranium, Iran would need a stockpile of 225 kilograms, which upon further enrichment to the weapons-grade level would yield the 25 kilograms of uranium metal for a nuclear warhead. Since it began enriching 20 percent uranium, Iran had produced 280 kilograms of this material – well above the Israeli red line drawn by Prime Minister Netanyahu. But it had removed a total of 112.6 kilograms of this 20 percent stockpile, leaving itself with a net total of 167 kilograms of 20 percent enriched uranium. This changed the entire timeline of the Iranian bomb, pushing it off from the fall of 2012 to a later date.

In May 2011, the IAEA raised concerns about the “possible existence” of seven areas of military research in the Iranian nuclear program, the last of which was the most alarming: “the removal of the conventional high explosive payload from the warhead of the Shahab-3 missile and replacing it with a spherical nuclear payload.” In November 2011, material that the IAEA presented pointed clearly to the fact that Iran wanted to develop a deliverable nuclear weapon. The planned warhead design also underwent studies that investigated how it would operate if it was part of a missile re-entry vehicle and had to stand up to the stress of a missile launch and flying in a ballistic trajectory to its target. The IAEA concluded that “work on the development of an indigenous design of a nuclear weapon including the testing of components” had been executed by the Iranians.

Iran is not a status quo power. A few years after he assumed the position of Supreme Leader of Iran, Ayatollah Ali Khamenei gave a revealing interview to the Iranian daily Ressalat, in which he asked a rhetorical question: “Do we look to preserve the integrity of our land, or do we look to expansion.” He then answered himself, saying: “We must definitely look to expansion.” This world view is still sustained to this day. Khamenei’s senior adviser on military affairs, Major General Yahya Rahim Safavi, who was the previous commander of the Revolutionary Guards, described Iran in 2013 as “the regional superpower” in the Middle East.

In the meantime, Iran has substantially increased the number of centrifuges that it installed for uranium enrichment. It also introduced its more advanced centrifuges into its nuclear facilities and it is making progress on its heavy water reactor that will allow it to produce plutonium. Iran, so far, has been careful not to cross the Israeli red line, but that hasn’t prevented it from moving ahead on other aspects of its program. Indeed, just after the last P5+1 talks in Kazakhstan, Tehran announced it was building 3,000 advanced centrifuges that it intended to install at Natanz.

Thus, if proposals are to be made that protect the international community as a whole from the threat of Iranian nuclear weapons, they must address other aspects of the program which might become fully operational in the years to come: the plutonium program, weaponization, delivery vehicles, and continuing upgrade of Iran’s centrifuge technology. If negotiations only halt one aspect of the Iranian effort to reach nuclear weapons, while letting the other parts of the program go forward, they may preclude an immediate crisis, but the world will still face a new Iranian challenge in the years ahead.

Over the last decade, a clear international consensus has slowly emerged that Iran was not just pursuing a civilian nuclear program, as Tehran argued, but rather was seeking nuclear weapons. True, the Nuclear Non-Proliferation Treaty guarantees the right of signatories, like Iran, to use nuclear energy for peaceful purposes, but that did not include a right to enrich uranium in order to produce indigenous nuclear fuels that could be employed for nuclear weapons.

Many countries with nuclear power infrastructures, like South Korea, Finland, Spain, and Sweden, actually received their nuclear fuels from abroad.1 Even in the U.S., 92 percent of the uranium used in 2010 by nuclear power plants was of foreign origin.2 But unlike these other cases, Iran chose to establish its own uranium enrichment infrastructure at Natanz and suspiciously kept it totally secret from the world until 2002, when it was revealed by the Iranian opposition. A second secret enrichment facility, near Qom, buried deep inside a mountain, was disclosed in 2009.

Because of the way Iran proceeded with its nuclear program, international suspicions of its purpose only increased. The official Iranian line that its nuclear infrastructure was for the production of electricity lost all credibility over time, especially in light of its enormous oil and gas reserves which were a far more economical source of energy. In February 2006, French Foreign Minister Philippe Douste-Blazy bluntly stated that “it is a clandestine military program.”3

Even the Russians could no longer protect what Iran was doing by saying that it was for purely civilian purposes. Thus, Russian President Dmitry Medvedev frankly admitted in July 2010, “We are not indifferent to how the military components of the corresponding [nuclear] program look.”4 Using careful language, James R. Clapper, President Obama’s Director of National Intelligence, reported to the Senate Select Committee on Intelligence on March 12, 2013, that Iran’s technical advancements “strengthen our assessment that Iran has the scientific, technical, and industrial capacity to eventually produce nuclear weapons.” For Washington, it was no longer a question of whether Iran wanted a nuclear bomb, but rather when it would decide to build it.

The Israeli View

In successive public appearances during the month of September 2012, Prime Minister Benjamin Netanyahu laid out what he believed was the timeline for Iran to cross the nuclear threshold and acquire an atomic bomb. In a September 16 interview with CNN’s Candy Crowley, he stated that the Iranians were moving into the final phase of their nuclear work, saying that they were entering a “red zone” in which they were coming extremely close to achieving their goal. He specified during the interview that this meant that within six months the Iranians will have accumulated a sufficient quantity of uranium at a level of enrichment that is 90 percent of the way to completing an atomic bomb.

The prime minister restated this same idea during his address to the UN General Assembly on September 27, when he said that after this 90 percent point, what he characterized as the final phase of enrichment would only require “a few months, possibly a few weeks.” Looking at the trends in the Iranian nuclear program as a whole, he warned during his address: “the hour is getting late, very late.” For that reason, he declared that a clear red line needed to be drawn in front of the leadership in Tehran before the Iranian program entered into this final phase of enrichment and was still within the second phase of enrichment.

To understand the phases of the Iranian program to which Prime Minister Netanyahu referred, it is important as background to recall that nuclear scientists have long explained the levels of enrichment as follows. Uranium comes in several isotopes: U-235, which can undergo nuclear fission, thereby releasing the explosive energy of an atomic bomb, and U-238, which is not usable for this purpose. But natural uranium is made up of only an infinitesimal amount of the potentially explosive U-235, approximately 0.7 percent, and a much larger proportion of U-238, approximately 99.3 percent. Enrichment involves increasing the percentage of U-235 isotope in uranium, usually by spinning uranium as a gas in thousands of centrifuges, and taking away the less useful U-238.

What did the prime minister mean when he said that Iran had reached level of enrichment with its uranium that is 90 percent of the way to a bomb? When uranium is enriched to the 3.5 percent level, in the first phase of enrichment, it is called low-enriched uranium and is mainly a suitable fuel for a civilian nuclear reactor producing electricity. Given the low starting point of U-235 in natural uranium, the amount of energy required to reach even this first level of low-enrichment is about 70 percent of the total energy needed to get to weapons-grade uranium. In other words, when Iran enriches uranium to the 3.5 percent level it has essentially advanced 70 percent of the way to the weapons-grade level.

More alarmingly, when Iran reaches the second level of enrichment, meaning 20 percent enriched uranium, it is essentially advancing 90 percent of the way to weapons-grade uranium. By beginning the last sprint to weapons-grade uranium from feedstock that is already at the 20 percent level, Iran could cut in half the time needed to undertake the same enrichment if it started with only 3.5 percent uranium. In short, a stock of 20 percent enriched uranium is ideally suited for what security experts call “nuclear breakout” – a rapid move by a state with what it declares to be a civilian nuclear industry if it wants move to a nuclear weapon, in violation of its commitments to the international community.

In his UN address, Prime Minister Netanyahu was saying that the international community must warn Iran that it will not be allowed to complete the production of enough 20 percent enriched uranium for its first atomic bomb. Like in his CNN interview, he stated during his UN address that Iran might cross this threshold by next spring or at the latest by next summer, but he carefully conditioned this assessment on the assumption that Iran maintains its current enrichment rates, leaving open the possibility that they could be accelerated.

For example, if Iran outfitted its uranium enrichment facilities with large numbers of more advanced centrifuges, like the IR-2M, that operate at four or six times the speed of the current IR-1 model they mostly use, then the rate of Iranian enrichment could be dramatically accelerated. Iran formally notified the IAEA on January 23, 2013, that it was going ahead and installing the IR-2M centrifuges. Alternatively, if Tehran installed and began to operate many more IR-1 centrifuges, then the volumes of uranium that the Iranians could process would also increase substantially.

The Failure of Past International Pressures on Iran

The world was not supposed to be in this kind of position at present. Since 2002, when the Iranian clandestine nuclear program was first revealed by the Iranian opposition, the main diplomatic assumption held across the international community was that a mixture of international sanctions and negotiations would force Iran to give up its military nuclear program. Subsequently, it was also thought that the threat of the use of force would compel Iran to halt its nuclear work.

Iran’s concealment of its nuclear activities, particularly its work on uranium conversion, uranium enrichment, and plutonium separation constituted outright breaches of its international obligations under its 1974 Safeguards Agreement that had been concluded in accordance with the 1968 Nuclear Non-Proliferation Treaty. Attention was particularly drawn at this time to the large uranium enrichment facility at Natanz.5

Iran’s violations of its treaty obligations were serious. As a result, diplomatic pressures were placed on Iran that appeared to be impressive. From 2006 onward, six UN Security Council resolutions were adopted that called on Iran to halt all uranium enrichment activity. Moreover, just like the resolutions adopted against Iraq under Saddam Hussein in the 1990s, these resolutions against Iran were adopted under Chapter VII of the UN Charter making them binding international law.

Yet this global effort against Iran clearly failed, for the resolutions plainly had no impact on Iranian decision-making. After UN sanctions were first imposed under Resolution 1737, in late 2006, the Iranians began enriching uranium anyway in February 2007 in ever growing quantities. It was also at this time that, despite UN pressures, Iran constructed a second secret enrichment facility, which was dug deeply into the side of a mountain at Fordow, near the city of Qom.

By 2009, Iran’s stocks of low-enriched uranium first went above 1,500 kilograms – the minimal amount for producing the quantity of weapons-grade uranium needed for a single atomic bomb. A little less than a year later, in February 2010, despite ongoing UN sanctions, Iran for the first time produced uranium at its Natanz facility enriched to the 20 percent level, which, as noted earlier, could be converted to weapons grade uranium in half the time in comparison with uranium at the low-enriched level. The Iranians began to enrich uranium to the 20 percent level at their Fordow facility in December 2011.

The Iranian regime also used these years to unilaterally alter the rules affecting the involvement of the International Atomic Energy Agency (IAEA) in its nuclear program in order to erode some of its most important restrictions. For example, Iran is required to notify the IAEA that it has decided to construct a new nuclear facility the moment such a decision is taken. In other words, even when construction begins for a new nuclear facility, the IAEA should be fully informed. In the technical jargon of the IAEA this obligation is known as “modified Code 3.1” and was formally accepted by Iran in an exchange of letters between Iran and the IAEA in February 2003.6

But in March 2007, Iran suddenly declared that it was suspending its acceptance of this obligation and going back to earlier IAEA rules that only required Tehran to declare a new nuclear facility six months before it receives nuclear material for the first time. This was not just a technicality. For having loosened the IAEA’s restrictions, the Iranians then argued that their formerly secret enrichment facility at Fordow, which was revealed in 2009, did not violate their legal obligations to the IAEA. Clearly the pressures placed on Iran by the UN Security Council during 2006 and 2007 were insufficient to prevent Tehran from taking such actions.

Then Tehran came up with the excuse that it needed 20 percent uranium for manufacturing medical isotopes at the Tehran Research Reactor. But the quantities of 20 percent uranium produced have by the admission of Iranian officials themselves exceeded their own domestic requirements for this purpose. Indeed, in an August 2011 interview published by the Iran News Agency, Fereydoun Abbasi-Divani, the head of the Iranian Atomic Energy Organization, admitted that the quantities of 20 percent enriched uranium produced “already exceeded the required amount for the Tehran Research Reactor.” The latest transparent excuse for further enrichment has been an Iranian proposal that they might have to enrich up to 90 percent uranium for powering nuclear reactors for future nuclear submarines.

Enriched uranium was not the only fuel that the Iranians planned to use for assembling a nuclear bomb. Since the first revelations about their nuclear program in 2002, it was known that Iran was building a heavy-water production plant at Arak, as well as a heavy-water nuclear reactor. Iran could extract plutonium fuel rods from the heavy-water reactor and reprocess them for producing weapons-grade material. The uranium route to an atomic bomb would still be shorter for Iran than the plutonium route, since Tehran will only first begin to operate its Arak reactor during the first three months of 2014, according to notification it gave to the IAEA.7

Time Line to an Iranian Bomb

If the countervailing pressures of the international community against Iran do not get it to halt its 20 percent enrichment, then when is it likely to obtain sufficient quantities of uranium at this level of enrichment that allow it to move quickly to the weapons-grade level and subsequently assemble its first nuclear bomb? According to the August 2012 IAEA report, Iran had already produced at that point a total of 189.4 kilograms of 20 percent uranium since it began to enrich to this level in February 2010.

To produce its first atomic bomb from 20 percent enriched uranium, according to the Institute for Science and International Security (ISIS), Iran would need a stockpile of 225 kilograms, which upon further enrichment to the weapons-grade level would yield the 25 kilograms of uranium metal for a nuclear warhead.8 In professional circles a “bomb’s worth” of high-enriched uranium is called a “significant quantity.” Iran should have been able to accumulate an adequate quantity of 20 percent uranium for one bomb by the end of October 2012, assuming it maintained its recent rate of production of 14.8 kilograms per month, using both of its enrichment facilities at Natanz and Fordow. Thus, the Iranians should have hit Prime Minister Netanyahu’s red line this past fall.

However, between December 2011 and August 2012, Iran drew down from its 20 percent stock by 96.3 kilograms, which it used to manufacture other uranium products, like uranium oxide powder for fuel plates. As a result, the net stock of 20 percent uranium fell to 91.4 kilograms. This changed the entire timeline of the Iranian bomb. According to the recent February 2013 IAEA report, Iran indeed continued its dual track approach to uranium enrichment in the first months of the year: it produced more 20 percent uranium and at the same time removed some of its 20 percent stock in order to produce other uranium derivatives that were not immediately useful for the eventual production of weapons-grade uranium. ISIS concluded on the basis of the February report that since it began enriching 20 percent uranium, Iran had produced 280 kilograms of this material – well above the Israeli red line drawn by Prime Minister Netanyahu. But it had removed a total of 112.6 kilograms of this stockpile, leaving itself with a net total of 167 kilograms of 20 percent enriched uranium.

Assuming Iran maintains its recent rate of production of 14.8 kilograms per month, and does not divert more 20 percent uranium for other uses, it should accumulate enough 20 percent uranium for a single bomb by the summer of 2013. For this reason, it is possible to project that Iran might hit the Israeli red line at that time. As stated earlier, this could happen even earlier if Iran manages to increase the rate of enrichment, especially if it utilizes centrifuges that have been installed but are not yet operational.9

For example, Iran installed 1,076 centrifuges in its Fordow facility between May and August 2012, bringing the number of centrifuges in Fordow alone to 2,140. Of that total only 646 centrifuges were actually operating. But Iran could substantially accelerate its production of 20 percent uranium in the months ahead if it decides to utilize all the new centrifuges it is in the process of installing. This would cut the time needed in half to produce enough 20 percent uranium that could be further enriched to the weapons-grade level.

Of course, Iran could reconvert its uranium oxide powder back to uranium gas for injecting into its centrifuges for further enrichment. Moreover, Iran also has a huge stock of 3.5 percent enriched uranium, which according to the February 2013 IAEA report reached 5,974 kilograms (after subtracting the uranium that was enriched to 20 percent). This stock alone could provide enough weapons-grade uranium for at least 3 to 4 atomic bombs, after further enrichment. But enriching from the 20 percent level would be the fastest way for the Iranians to break out and establish a fait accompli.

It is important to note that there are further steps that Iran must undertake to reach a nuclear weapon, whenever it amasses enough 20 percent uranium for its first bomb and enriches that stock to the weapons-grade level. Most estimates of the time needed to make this leap to weapons-grade uranium are between two and four months. All uranium enrichment requires uranium in a gaseous form: by spinning the gas at high speeds in a centrifuge the heavier U-238 can be separated from the lighter U-235, which is needed for a fission bomb. But once Iran has weapons-grade uranium as a gas, it needs to convert it into a metal for fashioning a nuclear warhead, which takes additional time.

The problem with precisely calculating time lines is also made complicated by the size of the weapon that Iran decides ultimately to make. As noted earlier, the IAEA established that further enrichment of this uranium must yield 25 kilograms of weapons-grade uranium for a nuclear explosive device. Yet critics charge that this number should be far lower. Even 15 kilograms of weapons-grade uranium would be sufficient for a bomb (historically, the U.S. conducted a nuclear test in 1951 with only six kilograms of high-enriched uranium).10

The Iranian timeline to an atomic bomb would thus be influenced by whether they seek to produce 25 kilograms of weapons-grade uranium or decide to settle on an initial device with less nuclear material and a smaller nuclear explosive yield. This difference could bring Iran much closer to crossing the nuclear red line much sooner.

Nuclear Warhead Design

There are, of course, three dimensions to any nuclear weapons program: enriched uranium, ballistic missiles, and nuclear warheads. The latter issue also grew in importance for the IAEA. This began to become evident in February 2008 when Olli Heinonen, then IAEA deputy director-general, gave a highly classified briefing to representatives of more than 100 states. According to a description of the meeting reported by David Sanger of The New York Times, Heinonen displayed original Iranian documents that he stressed came from several member states of the IAEA, and not just from the U.S.11 In June 2010, the German newspaper Der Spiegel reported that the material came from a joint operation by German and American intelligence agencies. The IAEA had the international standing to authenticate U.S. intelligence reports for those who doubted their veracity. When the IAEA said they were true, many more states were willing to accept them.

The Iranian documents detailed how to design a warhead for the Shahab-3 missile, which has been operational in the Iranian armed forces since 2003. While the Iranian documents made no reference to a nuclear warhead, they did show the arc of a missile’s flight and that the warhead of the missile had to be detonated at an altitude of 600 meters. To the IAEA experts, a conventional explosion at that altitude would have no effect on the ground below. But 600 meters was the ideal altitude for a nuclear explosion over a city. As Sanger points out, it was in fact the height of the Hiroshima explosion. Despite the substance of his presentation, Heinonen did not yet say that the Iranians were producing nuclear weapons, but he left his audience in Vienna with many questions they had not asked before.

By May 2011, the IAEA became far more explicit in its report on Iran than Heinonen had been in 2008. Its report raised concerns about the “possible existence” of seven areas of military research in the Iranian nuclear program, the last of which was the most alarming: “the removal of the conventional high explosive payload from the warhead of the Shahab-3 missile and replacing it with a spherical nuclear payload.”

Yet, the IAEA was not ready to say it had reached any conclusions. It only sought “clarifications” about its suspicions.

The most important of the IAEA reports on Iran was released in November 2011 and proved to be significant in a number of ways. First, it showed that the IAEA no longer had “suspicions” about the Iranian weaponization program – it had what it called “credible” intelligence. The appendix of the report, moreover, devoted a whole section to the “credibility of information.” It was not relying on the Iranian laptop that was at the heart of Heinonen’s 2008 presentation, but also on a much larger volume of documentation. The report states that the agency has more than 1,000 pages of material to substantiate its claims. In case there were suspicions that this material came from U.S. intelligence agencies alone, the report makes sure to clarify that the sources involved “more than 10 member states.”

Second, the material that the IAEA presented pointed clearly to the fact that Iran wanted to develop a deliverable nuclear weapon. The Iranians had sought to obtain uranium for a secret enrichment program that would not be under IAEA safeguards. The uranium that would come out of this clandestine program would be further processed to produce the uranium metal required for a nuclear warhead. The planned warhead design also underwent studies that investigated how it would operate if it was part of a missile re-entry vehicle and had to stand up to the stress of a missile launch and flying in a ballistic trajectory to its target. The IAEA concluded that “work on the development of an indigenous design of a nuclear weapon including the testing of components” had been executed by the Iranians.

Why Does Iran Persist with Its Nuclear Drive?

Iran’s audacity in violating its international obligations has surprised many in the West. The Iranian government has paid a steep economic price in terms of international sanctions, but nevertheless continues its drive to obtain nuclear weapons. It is impossible to separate Iran’s determination to acquire nuclear weapons from its broader ambitions to become the preeminent power in the Middle East.

For Iran is not a status quo power. A few years after he assumed the position of Supreme Leader of Iran, Ayatollah Ali Khamenei gave a revealing interview to the Iranian daily Ressalat, in which he asked a rhetorical question: “Do we look to preserve the integrity of our land, or do we look to expansion.”12 He then answered himself, saying: “We must definitely look to expansion.” In essence, he was reflecting what is written in the Constitution of the Islamic Republic, which calls for the “continuation of the Revolution at home and abroad.”13 Khamenei is the commander-in-chief of the Iranian armed forces and hence his definitions of Iranian national strategy are essential to follow.

This world view is still sustained to this day. Khamenei’s senior adviser on military affairs, Major General Yahya Rahim Safavi, who was the previous commander of the Revolutionary Guards, described Iran in 2013 as “the regional superpower” in the Middle East.14 He asserted that a “new global power is emerging in the Muslim world.” He explained that Washington was trying to prevent this from happening.

In the last five years, Iranian spokesmen close to Khamenei have voiced expansionist goals for the Islamic Republic, insisting that Bahrain is an Iranian province and reminding the other Arab Gulf states that they used to be part of Iranian territory. Moreover, on the ground, Khamenei uses the Qods Force of the Revolutionary Guards, under the command of Major General Qassam Suleimani, throughout the Middle East in order to export its revolutionary agenda.

Two years ago, The Guardian reported that a senior Iraqi politician gave General David Petreaus a text message in 2008 from Suleimani that read: “General Petraeus, you should know that I, Qassem Suleimani, control the policy for Iran with respect to Iraq, Lebanon, Gaza, and Afghanistan.”15 This story was partly verified this January, when the Iranian newsagency ISNA reported that in a speech about Lebanon and Iraq, Suleimani asserted: “These regions are one way or another subject to the control of the Islamic Republic of Iran and its ideas.”16 Also in January, Iran admitted for the first time that the Quds Force had been deployed in both Lebanon and Syria.

In terms of the Iranian nuclear program, the distinction that Khamenei made between defensive goals for the Islamic Republic, which he did not adopt, and the offensive doctrine that he appeared to embrace, means that an Iranian nuclear weapons capability would not be for the purpose of deterrence alone, as with many other regimes, but for serving its drive to achieve regional hegemony and improve its power position vis-à-vis its Arab neighbors and the U.S. Ali Larijani, who once served as the National Security Advisor of Iran and as its chief nuclear negotiator, made this very point, asserting that “if Iran becomes atomic Iran, no longer will anyone dare challenge it because they would have to pay too high a price.” In short, nuclear weapons secure Iran’s status as a great power that does not have to accept the demands of any other power.17

Larijani’s remark is important for understanding another feature of Iran’s drive to cross the nuclear threshold. Recent history demonstrates that once a state like North Korea conducted its first nuclear test, then the U.S. and its Western allies became reluctant to challenge its nuclear status. In contrast, once Libya gave up its nuclear weapons program, the U.S. and its NATO allies felt free to back the revolt in 2011 against the regime of Muammar Gaddafi. Thus advances in the Iranian nuclear program could put it in a position in the near future to be able to deter even the U.S. from taking action against its nuclear facilities because of the risks involved.

Clearly, there are a number of benchmarks that Iran must traverse on its way to a full nuclear weapons capability. First, there is the completion of the minimal quantity of 20 percent enriched uranium needed for manufacturing an atomic bomb after it is enriched further to weapons-grade uranium. Second, there is the manufacture of uranium metal that is used in a nuclear warhead. Third, there is the production of the warhead itself and it being outfitted on a ballistic missile, like the Shahab-3, that can strike Israel, Saudi Arabia, or Turkey, as well as Western forces deployed in those countries. The November 2011 IAEA report on Iran concluded that Iran had worked on a nuclear warhead. A top Israeli official specified that Tehran had already undertaken activities “to integrate a payload on a Shahab-3 missile.”18

The Final Stages of the Iranian Nuclear Program

As Iran advances in its nuclear program, it undoubtedly acquires a great degree of deterrence even before it has a fully operational weapon. Looking at the example of North Korea, it removed IAEA surveillance equipment and evicted its nuclear inspectors in December 2002, while telling U.S. officials that it had nuclear weapons in April 2003. The North Koreans only conducted their first nuclear test in 2006 and a second test in 2009. From their experience, the North Koreans probably raised concerns in the West about their having an impending nuclear weapons capability even before their first nuclear test. Two U.S. analysts have written that the U.S. already began adjusting its military planning on North Korea in the late 1990s when intelligence analysts concluded that North Korea was capable of assembling a nuclear weapon. The point is that rogue states began acquiring strategic advantages from nascent nuclear programs even before they make the final assembly of a nuclear warhead for their missiles.19

How would this work in the case of Iran? As the indications mount in 2013 that Iran is making its final preparations to cross the nuclear threshold and become a nuclear weapons state, there will be a renewed debate in the West over the question of the use of military force. But that debate will be clouded with the question of whether Iran already has nuclear weapons. Presumably those who will assert that Iran already has nuclear weapons will argue that any preventive strike will be too risky at this point in time. The main problem is that at this stage intelligence agencies will be operating largely in the dark.

This point has been made occasionally even by senior levels in the U.S. Appearing on NBC’s “Meet the Press,” on April 11, 2011, former Secretary of Defense Robert Gates made this very point: “If they – if their policy is to go to the threshold but not assemble a nuclear weapon, how do you tell that they have not assembled? So it becomes a serious verification question, and I, I don’t actually know how you would verify that.” Gates’ assessment was particularly significant given the fact the he served as the Director of the CIA in the 1990s and understood better than most officials the true limits of Western intelligence agencies when it comes to the detection of weapons of mass destruction programs.

This explains the enormous risks of letting the Iranian nuclear program progress to its final stages, when Western knowledge about how far Iran has progressed will be problematic. Indeed, Prime Minister Netanyahu made this very point during his UN address. He noted that the Iranian enrichment facilities containing thousands of spinning centrifuges were “very big industrial plants.” That meant they were both visible and vulnerable. However, he added that once the Iranian weapons program has moved on to the next stage involving the production of a nuclear detonator, then it would no longer be reliant on large plants but rather could be completed in a small workshop that is the size of a classroom. At the very final phase of Iran’s nuclear activity, it would be far less visible to Western surveillance and hence it would be far less vulnerable.

It is for this reason that Israel has had to draw its red line on Iran’s drive for nuclear weapons on the enrichment phase of the program and not wait for the weaponization phase which would be too late. In summary, it is difficult to say with precision when Iran will acquire enough 20 percent uranium that can be enriched further to the weapons-grade level for the manufacture of an atomic bomb. But what is clear is that this moment in time is fast coming close and Iran must be halted well before it arrives. In the meantime, according to the latest IAEA report, Iran has substantially increased the number of centrifuges that it installed for uranium enrichment. It also introduced its more advanced centrifuges into its nuclear facilities and it is making progress on its heavy water reactor that will allow it to produce plutonium.20

In the present negotiations between the P5+1 and Iran, the West will undoubtedly be cognizant of Israel’s focus on uranium enrichment to the 20 percent level and the red line drawn by Prime Minister Netanyahu. Iran, so far, has been careful not to cross the Israeli red line, but that hasn’t prevented it from moving ahead on other aspects of its program. Indeed, just after the last P-5 plus 1 talks in Kazakhstan, Tehran announced it was building 3,000 advanced centrifuges that it intended to install at Natanz.

Thus, if proposals are to be made that protect the international community as a whole from the threat of Iranian nuclear weapons, they must address other aspects of the program that were discussed here and which might become fully operational in the years to come: the plutonium program, weaponization, delivery vehicles, and continuing upgrade of Iran’s centrifuge technology. If negotiations only halt one aspect of the Iranian effort to reach nuclear weapons, while letting the other parts of the program go forward, they may preclude an immediate crisis, but the world will still face a new Iranian challenge in the years ahead.

14. "Iran is Superpower of the Region;" New Axis of Power in Islamic World is Now Being Formed," Iran Daily Brief, February 7, 2013, http://www.irandailybrief.com/2013/02/07/iran-is-superpower-of-the-region-new-axis-of-power-in-islamic-world-is-now-being-formed/